Delta-sigma data converters have gained popularity in both analog-to-digital and digital-to-analog converters (ADCs and DACs) due to their simplicity, high linearity and immunity to many analog circuit imperfections. These data converters include features such as oversampling, noise-shaping, and (historically) single-bit quantization. Single-bit converters are preferred for their inherent linearity. This...
The precise measurement of a capacitance difference or ratio in a digital form is
very important for capacitive sensors, for CMOS process characterization as well as for the
realization of precise switched-capacitor data converters, amplifiers and other circuits
utilizing ratioed capacitors. This thesis introduces design techniques for on-chip capacitor
ratio...
Pulse Width Modulation (PWM) has been used extensively for motor control, DC-AC
converters, DC-DC converters and in audio applications. The conventional method of
generating a pulse width modulated signal involves generating an accurate sawtooth or triangle
wave using analog circuits. In CMOS, being analog circuit intensive puts extra constraints
on...
This thesis describes compensation techniques for cascaded delta-sigma A/D
converters (ADCs) and high-performance switched-capacitor (SC) circuits. Various
correlated-double-sampling (CDS) techniques are presented to reduce the effects of the
nonidealities, such as clock feedthrough, charge injection, opamp input-referred noise and
offset, and finite opamp gain, in SC circuits. A CDS technique...
Oversampled analog-to-digital (A/D) converter architectures have been receiving
increased attention for high-precision A/D converters. These architectures offer the
means of exchanging resolution in time for that in amplitude. Among these
oversampled A/D converters, delta-sigma modulators are the most popular method
used due to their simplicity in the analog circuitry. The...